1. Field of the Invention
Embodiments of the present invention generally relate to digital filtering communication systems. More specifically, the present invention relates to a method and apparatus for the efficient reduction of a wide dynamic range of a signal.
2. Description of the Related Art
In many communication systems that employ digital filtering (e.g., channel selectivity), a wide signal dynamic range is produced in order to realize the full processing gain of the filter, to produce a high level of adjacent channel/blocker performance, and to reduce quantization noise. In receivers where channel selectivity functions are performed in the digital domain, very wide dynamic range signals (e.g., 16-bit+) are typically utilized to achieve high levels of linearity and selectivity. However, these wide signal dynamic ranges may present challenges for processing the signal in the phase domain (e.g., for any type of m-ary phase demodulation). In order to reduce the complexity of m-ary phase shift keying (PSK) receivers, it is often desirable to perform the required signal processing in the phase domain. This requires the conversion of the wide dynamic range complex baseband signal into a phase domain signal. Generally, the key to achieving an efficient design (e.g., low cost and high performance) for a digital demodulator is to reduce the dynamic range of the signal before converting to the phase domain, while simultaneously retaining a requisite amount of amplitude data by utilizing the same hardware resources. In this manner, a fully linear receiver along with its associated complexity (e.g., large look-up tables, costly quadrature signal computations, etc.) can be avoided.
Thus, there is a need in the art for an efficient method and apparatus that efficiently reduces the dynamic range of a signal while producing accurate phase information.